The Arecibo imperative

For those that question the importance of Arecibo Observatory. A document was signed by 100 important scientists, astronauts, entrepreneurs, and celebrities focused on the asteroid impact danger. The attention was explosive, certainly helped from the inclusion of two ex-astronauts, Ed Lu and Rusty Schweickart, under whose guidance the B612 Foundation has tackled the asteroid threat joined by the ubiquitous Bill Nye, president of the Planetary Society, after all, to protect the planet from impact is a good thing. And since nobody can scientifically foresee the exact possible location and all the planet is equally exposed it is a humanity concern.

The question arises, then: What exactly is our current best knowledge about the real danger of future impacts? From all that astronomers have learned about asteroids over the past generation, they know that the danger from near-Earth objects is very real.

The risk to Earth from impacts is clearly significant from the near-Earth object population. The risk from asteroids impacting Earth and causing widespread damage, death, and catastrophe is real, and is present every day of our lives. But it is to a degree a counterintuitive threat. If you multiply the impact frequency by the area affected, the larger events are more frequent. That balance is changing as planetary scientists discover more bodies, but the fact remains that the risk is still slightly greater from the remaining undiscovered big objects than from the small ones.

Understanding the risks from asteroid impacts on Earth is a pretty young exercise, as is the case with much of astronomy and planetary science. We now know that future dangerous impacts will happen, though they may be many years away. From a planetary scientist’s view, however, it would be grossly negligent to avoid completing as thorough a survey as possible of all the space rocks in Earth-crossing orbits and understanding other small bodies farther out in the solar system that could come our way.

Perhaps we will discover incoming asteroids and be able to divert their orbit before disaster strikes. We damn sure will want to be ready when that day comes. Anything less would be a reckless misuse of the knowledge our species has worked so hard to gain.

What's out there? 

So far, NASA has classified more than 21,000 asteroids and more than 100 comets as near-Earth objects. Of that group, about 2,000 are considered "potentially hazardous," meaning they have orbits within 4.5 million miles of Earth and are big enough to cause massive devastation on impact. Congress has directed NASA to find and track at least 90 percent of the objects measuring 459 feet in diameter or larger and that pass within 30 million miles of Earth's orbit. But scientists have identified only an estimated 40 percent of near-Earth objects. 

Why was Arecibo so important? Let's stick to facts: 

Researchers were stunned in July when a previously undetected "city killer" asteroid that was up to 427 feet wide came within 45,000 miles of Earth — less than one-fifth the distance to the moon. If the asteroid had struck the Earth, "it would have gone off like a very large nuclear weapon," said Michael Brown, an observational astronomer at Australia's Monash University. As soon as it was identified Arecibo focused on it and could map its route, describe it snd its rotation even its surface. Only Arecibo had that technical ability. So as close as of Thursday 25 July, 2020, an unknown and unidentified asteroid 57-130 meters across missed our planet by just one-fifth of the distance to the moon. In astronomical terms, that’s a hair’s breadth. Had it hit us, the devastation would have been staggering. 

More facts: In February 2013, one roughly 20 meters across appeared in the sky above the Russian city of Chelyabinsk. It exploded at an altitude of around 30 kilometers, creating a shockwave that shattered windows and injured around 1,500 people, and extended its impact some 58 miles.

Says Mike Willis of the UK Space Agency, "We’re living on borrowed time. If we lose the science (like losing Arecibo), we will be effectively blind. And we don’t want to be in that situation,” says Willis.

People are too complacent about the asteroid threat for Bill Nye's liking. "The Earth is going to get hit with another [big] asteroid," Nye said at the International Academy of Astronautics Planetary Defense Conference in College Park, Maryland. "The problem is, we don't know when," he added. But there are lots of undiscovered asteroids zooming through near-Earth space that could do serious damage on a local scale — wiping out an area the size of a state, for example. So, it would behoove us to have better tools online, Nye said.

The truth of the matter is we just lost our best tool to study asteroids when we lost Arecibo, it is a fact that the scientific community acknowledges though the NSF and NASA have tried to downplay its importance mainly because it is their fault.

Back to the facts: 

"Asteroid 2020 NK1 was spotted in early July by the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey team at the University of Hawaii. Little was known about the asteroid, making it difficult to predict exactly where the asteroid would travel in the future. It was estimated to be 1,600 feet in diameter, about the length of five football fields. Before the Arecibo observations, 2020 NK1 was calculated to be one of the biggest threats out of all known asteroids on NASA's list of potential impactors, with about one chance in 70,000 of impacting the Earth between 2086 and 2101.

Arecibo’s Planetary Radar Group made it a priority to observe 2020 NK1 when it came within range – within 5 million miles – of the facility’s powerful instruments. In this case, the time period was brief, July 30-31, just about the same time Tropical Storm Isaias was expected to slam into the island.

The observatory shut down to prepare for the storm, and as soon as it passed the team jumped into action to detect and study the asteroid. Even as parts of the island lost power and damage was assessed, the Arecibo team was able to determine the asteroid’s shape, orbit, and motion." (NASA)

https://solarsystem.nasa.gov/news/1421/arecibo-observatory-returns-from-tropical-storm-isaias-lockdown-to-track-asteroid-for-nasa/

Planetary Society Reacts to Loss of Arecibo Observatory Radio Telescope:

"Of immediate concern is the telescope’s role in tracking and characterizing asteroids. Arecibo’s planetary radar was the most powerful in the world, observing roughly 100 near-Earth asteroids per year. Half of those were newly discovered objects whose orbits were not precisely known. Arecibo observations helped scientists determine whether an asteroid would hit our planet and ensured their trajectories were catalogued for future observations. Arecibo’s size allowed it to reach farther asteroids.

“Arecibo’s ability to characterize near-Earth objects using radar was a real asset for the planetary defense community,” said Planetary Society chief scientist Bruce Betts. The Planetary Society’s connections to Arecibo include SETI, the search for extraterrestrial intelligence." 

The Arecibo Observatory was the largest radio telescope in the world and a point of pride for Puerto Ricans, whether they were in science or not. About 90,000 islanders and tourists visited the observatory every year. 

When the Arecibo telescope collapsed, the world lost its most powerful asteroid tracker. In its 57 years of radio astronomy, Arecibo tracked potentially hazardous asteroids, discovered the first exoplanet, and broadcast a message for aliens.

The structure was used to track asteroids and meteorites near the Earth and served as an environmental and meteorological reference for its tools to analyze the atmosphere.

It was also known for its role in helping discover the first-ever binary pulsar in 1974, which eventually earned radioastronomer Joseph Taylor and physicist Russell Hulse a Nobel Prize in physics.

As Space declared: 

"After Arecibo, NASA isn't sure what comes next for planetary radar..."

“Many scientists have worked on this telescope over the last 50-plus years,” said Thomas Zurbuchen, head of NASA’s science directorate. “Those observations have provided tremendous insights in some of the most energetic parts of our universe, pulsars. They have provided important planetary science looking at the moon and Mars … And also they have contributed tremendously to planetary defense objectives.”

Lindley Johnson, NASA’s planetary defense officer, said “Arecibo had the range, so the planetary science at more distant objects will suffer the greatest impact,” Johnson said “We will no longer have the range that Arecibo offered."

“Approximately 65 percent of the estimated 1,100 large near-Earth objects (those larger than 1 kilometer or .62 miles) have already been discovered, with 45 percent discovered since 1998.” (NASA)

https://www.nasa.gov/vision/universe/watchtheskies/near_earth052104.html

PachiOrtizfeliciano

#RebuildAreciboObservatory

EdNote: The illustration is an artístic representation by NASA of an asteroid in relation to Earth based on their modeling.